June 22 (UPI) — Traffic fatalities have increased in Colorado since the state legalized the use of recreational marijuana, an analysis published Monday by JAMA Internal Medicine has found.
Since the state opted to legalize recreational use of the drug in 2014, there have been an additional 75 deaths resulting from traffic accidents, on average, annually, the researchers estimated.
Conversely, Washington State, which lifted prohibitions on marijuana the same year, has seen traffic-related deaths remain relatively stable, they said.
“Colorado and Washington State recreational cannabis laws differ in many ways, including purchasing limits, sales taxes, ability to grow cannabis at home and density of retail stores,” researchers wrote in the study.
“These factors may have contributed to higher cannabis availability and driving under the influence in Colorado than in Washington State,” they wrote.
To date, 11 states and Washington, D.C., have legalized marijuana. These states have changed the way they define — and prosecute — impaired driving as a result, according to research.
Earlier studies have suggested that traffic accidents in general have increased in many of these states since the drug was legalized.
For the new analysis, researchers of the JAMA Internal Medicine study reviewed data on traffic fatalities in both states from the Fatality Analysis Reporting System. Their review covered a 12-year period from 2005 through 20017.
To estimate differences, the researchers created “synthetic controls” for both states, an approach that uses an algorithm to identify a combination of states from a pool of control states with similar traffic fatality rates.
Compared to its synthetic control, Colorado since legalization has seen 1.46 traffic deaths per 1 billion vehicle miles traveled, or VMT, per year, they found. Washington State, however, has had 0.08 deaths per 1 billion VMT per year since legalization, they said.
“These findings suggest the need for policies, public health programs and enforcement strategies that will prevent unintended consequences of cannabis legalization,such as increased rates of traffic injuries,” the authors wrote.